Question

What is the mass of a photon of sodium light with a wavelength of 5890 Å?
[h= 6.626 × 10⁻³⁴ Js]

Answer 1

Given conditions ⇒

Wavelength(λ) = 5890 Angstrom. 
= 5890 × 10⁻¹⁰ m. 
Plank's constant (h) = 6.626 × 10⁻³⁴ J-s.
Speed of the light(c)= 3 × 10⁸ m/s.

Using the Formula,
  λ = h/mc   
5890 × 10⁻¹⁰ =  6.626 × 10⁻³⁴/(m × 3 × 10⁸)
17670 × 10⁻² m = 6.626 × 10⁻³⁴
m = 0.00037 × 10⁻³²
m = 3.7 × 10⁻³⁶ kg.


Hence, the mass of the photons is 3.7 × 10⁻³⁶ kg.


Hope it helps.

Answer 2

Answer:

Given conditions ⇒

Wavelength(λ) = 5890 Angstrom. 

= 5890 × 10⁻¹⁰ m. 

Plank's constant (h) = 6.626 × 10⁻³⁴ J-s.

Speed of the light(c)= 3 × 10⁸ m/s.

Using the Formula,

  λ = h/mc   

5890 × 10⁻¹⁰ =  6.626 × 10⁻³⁴/(m × 3 × 10⁸)

17670 × 10⁻² m = 6.626 × 10⁻³⁴

m = 0.00037 × 10⁻³²

m = 3.7 × 10⁻³⁶ kg.